The present invention relates to bearings per se and to the combination of a bearing housing and a bearing, wherein the lubrication of the bearing is facilitated.
It is conventional to provide a bearing housing with a reservoir intended for containing lubricant oil and means adapted to transport the lubricant from the reservoir to the raceway of the outer ring of the bearing.
In arrangements of that type, the raceways of the bearing are usually lubricated by having lubricant flowing thereto by gravity. The amount of lubricant, then, must be large enough to ensure that the lubricant level is higher than the lowest point on the raceway of the outer ring over the whole width of the bearing. The amount of lubricant, thus, becomes comparatively large which causes a comparatively high operating temperature of the bearing, because a grater amount of lubricant is being squeezed or worked by the rotary elements of the bearing.
It is also previously known to supply lubricant to the bearing surface in a bearing by means of a felt strip by having a portion of the felt strip submerged in the lubricant and arranging the felt strip in direct connection with the bearing surface. However, this basic type of lubricating arrangement, which is shown in for instance U.S. Pat. No. 2,538,075 can be used only in friction bearings.
It is also known from U.S. Pat. No. 1,687,668 to mount the end of a rotary shaft within a bearing bushing and to provide grooving in the bushing which receives a wick. A lower end of the wick dips into a reservoir of lubricant so that the wick conducts the lubricant around the periphery of the bushing. Radial through holes formed in the grooving enable the lubricant to gravitate into the space between the bushing and rotary shaft. The wick is sized to project radially well beyond the open side of the groove in order to reach the lubricant. As a result, the distance which the lubricant must travel before reaching the through holes is greater. Also, the lubricant is not confined within the wick and thus may flow from the wick and onto the outer periphery of the bushing before reaching the through holes. Furthermore, the grooving does not extend in a circular path as viewed along the axis of the shaft, but rather extends in a rectangular or oval path. Consequently, the circumferential distance which the lubricant must travel before reaching the through holes is longer, and the lubricant may have to travel around corners which could inhibit the flow.
A main object of the present invention is to provide an arrangement for lubricating a rolling bearing mounted in a bearing housing, wherein the lubricant level can be kept low, thereby ensuring a lower operating temperature of the bearing.